Ischemia or infaraction of the heart is known to generate a steady (dc) injury current. Knowledge of this current would be clinically important, but it cannot reliably be measured with electrodes on the skin, because it would be masked by large potentials generated in the skin. However, the dc magnetocardiogram (dcMCG) responds only to current, hence is not affected by the skin potentials because they produce no current in the high-resistance skin; it can therefore reliably (and non-invasively) measure the injury current. The dcMG shows the same features as the ECG, (QRS, T, P). In addition, the baseline level indicates the dc of the heart. In a previous study of dogs undergoing experimental myocardial infarction, the dcMG was sucessfully used to determine whether or not the S-T shift was a secondary event due to an interrupted injury current; this type of event was signified by a baseline shift which was equal and opposite to the S-T shift, regardless of the detection point around the torso. We here propose to extend the use of the dcMG to the human heart and, with this new technique, to clarify some features of the clinical ECG. We propose, specifically, to determine whether or not the S-T shift is a secondary event, due to an injury current, or a primary event, in the following groups of patients; normal but showing S-T elevation; with BBB and S-T shift; with LV aneurysm and S-T shift. Normal subjects will also be measured as a control group. The measurements will be made with a new magnetic detector which allows correlation with surface potential maps and the ECG.